• Martin Schwidefsky's avatar
    s390/mm: implement software referenced bits · 0944fe3f
    Martin Schwidefsky authored
    The last remaining use for the storage key of the s390 architecture
    is reference counting. The alternative is to make page table entries
    invalid while they are old. On access the fault handler marks the
    pte/pmd as young which makes the pte/pmd valid if the access rights
    allow read access. The pte/pmd invalidations required for software
    managed reference bits cost a bit of performance, on the other hand
    the RRBE/RRBM instructions to read and reset the referenced bits are
    quite expensive as well.
    Reviewed-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    0944fe3f
vmem.c 9.59 KB